Couldn't find the 'yo' binary when installing hubot and Yeoman

Question

I'd like to install Yeoman, but still get the error below. I have tried my best but failed.

I want to install hubot generator and type:

npm install -g yo generator-hubot

The error is as follows

I try to reinstall npm and nodejs but didn't work. But I'm not sure my NODE_PATH is right,I don't know how to set it.

NODE_PATH is as follows:

I'm new to this field and really don't know how to do.
Thanks a lot.